The present invention relates to the art of material treatment. It finds particular application with a vacuum pneumatic conveying system to deliver plastic pellet material to a belt conveyor. The pellets are carried on the belt conveyor past an electron beam source for irradiation treatment. It is to be appreciated that the present invention is also applicable to the treatment of other materials, such as grains, seeds, other polymers, and the like.
Currently, plastic pellets are loaded in trays to be conveyed through an irradiation unit. Typically, the trays are raked and sent through the unit again for retreatment until an appropriate total radiation dose is reached. This prior system has drawbacks including the large amounts of manual labor, consistent dose assurance, and problems attributable to heating of the polymer material of the pellets.
The present invention contemplates a new and improved apparatus and method which overcome the above referenced problems and others.
In accordance with one aspect of the present invention, an apparatus is provided for irradiating particulate material. The particulate material is suspended in a moving fluid and conveyed to a source of radiation. The pelletized material is passed at a controlled rate through the radiation. The pelletized material is fluidized and conveyed from the radiation, the fluidizing concurrently cooling the pelletized material.
In accordance with a more limited aspect of the present invention, the pelletized material is deposited in a layer of uniform thickness on a belt conveyor prior to passing through the radiation and is removed from the belt conveyor and refluidized after irradiation.
In accordance with another more limited aspect of the present invention, the pellets are a polymeric material which pass through the radiation at a known rate to achieve a preselected polymerization reaction.
In accordance with another aspect of the present invention, the fluidized particulate material is passed through the radiation while suspended in the fluid.
In accordance with yet another aspect of the present invention, fluids themselves, such as liquid sewage, waste water, stack gasses, and the like, are treated by the radiation beam.
A principle advantage of the present invention is the provision for transporting loose particulate material passed an irradiation source at a controlled rate.
Another advantage of the present invention is that plastic pellets are treated with an accurately controlled dose of radiation.
Still another advantage of the present invention is manual labor and human process variations are minimized.
Yet another advantage of the present invention is that particulate material is entrained, irradiated and recollected into the same container, all without human intervention.
Still further advantages of the present invention will become apparent to those of ordinary skill in the art upon reading and understanding of the following detailed description of the preferred embodiment.